Aircraft pneumatic and air conditioning systems, as described in SAE ARP85F, are typically used on subsonic commercial aircraft to maintain adequate environmental conditions within the aircraft cabin. The system usually comprises an arrangement of equipment, controls and indications that supply and distribute conditioned air to the aircraft cabin and compartments in a way that avoids overheating or overcooling due to the thermodynamic balance of the compartments. Such systems contemplate and consider occupants' body heat transfer, solar radiation, electrical equipment thermal dissipation, convection with the external ambient air temperature. In addition, the air conditioning system supplies an amount of fresh air into the aircraft cabin to ensure air quality by maintaining the levels of gases such as oxygen, carbon dioxide, carbon monoxide and it also supports the pressurization of the aircraft cabin.
In some non-limiting applications, it may be desirable to optimize, reduce or minimize the consumption of bleed airflow diverted from gas turbine engines (reducing fuel consumption).